VOC and odor reducing building panels

ABSTRACT

Described herein is a building panel comprising a substrate and an odor and VOC reducing coating applied to the substrate, the coating comprising a blend of a first component comprising ethylene urea; a second component comprising silica; and a rheology modifier.

FIELD OF THE INVENTION

The present invention relates generally to a coating suitable forneutralizing VOCs and/or odors in a closed environment. The coatingcomposition may comprise an odor-reducing coating composition that maybe applied to one or more building panels.

BACKGROUND OF THE INVENTION

Previous VOC and/or odor-reducing building panels were limited by lackof variety of VOCs and/or odors that could be neutralized as well as thelimited extent to which VOCs and/or odors could be neutralized over aset period of time. Furthermore, previous attempts at forming a VOCand/or odor-reducing panel were limited by application methodologiesthat either degraded the neutralizing agent during manufacture orlimited the amount of neutralizing agent that could be properly applied.

BRIEF SUMMARY OF THE INVENTION

The present invention may be directed to a VOC and odor-reducingbuilding panel comprising a substrate and a coating applied to thesubstrate, the coating comprising a blend of a first componentcomprising ethylene urea; a second component comprising silica; and arheology modifier.

Other embodiments of the present invention may include a VOC andodor-reducing building panel comprising a substrate and a coatingapplied to the substrate, the coating comprising an odor reducing blendthat comprises ethylene urea and silica in a weight ratio ranging fromabout 1:1 to about 1:8; wherein the coating is substantially solid atroom temperature and comprises less than 5 wt. % of moisture based onthe total weight of the coating.

Other embodiments of the present invention include a method of forming aVOC and/or odor-reducing building panel comprising: providing asubstrate; applying a wet-state coating composition to a major surfaceof the substrate, the wet-state coating composition comprising: a blendof ethylene urea and silica; and a carrier comprising water; and dryingthe wet-state coating composition thereby evaporating at least 95 wt. %of the carrier to form a dry-state coating composition.

Other embodiments of the present invention include a VOC andodor-reducing building panel comprising: a substrate; and a coatingapplied to the substrate, the coating comprising an odor-reducingcomposition consisting essentially of silica gel.

Other embodiments of the present invention include a VOC andodor-reducing building panel comprising: a substrate; and a coatingapplied to the substrate, the coating comprising: silica gel; asurfactant; and a rheology modifier.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

In the description of embodiments of the invention disclosed herein, anyreference to “about” or “substantially” refers to a difference of +/−5%of the referenced amount. In the description of embodiments of theinvention disclosed herein, any reference to “substantially free” refersto less than 3 wt. % of the referenced amount.

The present invention is directed to installation systems comprising atleast one building panel, the building panel comprising a substrate anda VOC and odor-reducing coating (referred to herein as the “coating”)applied thereto. The coating comprises a VOC and odor-reducingcomposition (referred to herein as “reducing composition”) that includesa blend of a first component that comprises a urea compound and a secondcomponent that comprises silicon dioxide (as referred to as silica).

The substrate may be formed from an organic material, an inorganicmaterial, and combinations thereof. Non-limiting examples of inorganicmaterial include gypsum board (e.g., sheetrock), calcium carbonate, clay(i.e., kaolin), expanded-perlite, mineral wool fibers (e.g., slag wool,rock wool, and stone wool), fiberglass, or a combination thereof.Non-limiting examples of organic material include cellulosic fibers(e.g. paper fiber, hemp fiber, jute fiber, flax fiber, or other naturalfibers), polymer fibers (including polyester, polyethylene, and/orpolypropylene), protein fibers (e.g., sheep wool), and combinationsthereof.

The substrate may be a porous structure formed from organic and/orinorganic fibers that are bonded together with the aid of a binder.Non-limiting examples of binder may include a starch, latex, or thelike. The substrate may be a porous body. The porosity of the substratemay allow the building panel to exhibit an acoustical absorbency highenough to reduce noise in an interior environment, thereby allowing thebuilding panel to function as an acoustical ceiling panel—as discussedfurther herein.

The substrate may comprise a first major surface opposite a second majorsurface and side surfaces that extends between the first major surfaceand the second major surface. The substrate may have a thickness asmeasured from the first major surface to the second major surface—thethickness ranging from about 0.25 inches to about 2 inches—including allvalues and sub-ranges there-between. The coating may be applied to atleast one of the first major surface or the second major surface of thesubstrate.

The coating may be applied to at least one of the first or second majorsurfaces of the substrate in a wet-state. The term “wet-state” refers tothe coating comprising the reducing composition as well as acarrier—such as water. The carrier may comprise at least 95 wt. % ofwater—based on the total weight of the carrier. In a preferredembodiment, the carrier is 100 wt. % of water. After application of thecoating in the wet-state, the carrier may be driven off yielding thecoating in a dry-state applied to the substrate. The term “dry-state”refers to the coating being substantially solid at room temperature(i.e., about 21° C. to about 23° C.) have less than 5 wt. % of moistureand being substantially free of carrier based on the total weight of thecoating.

In the dry-state, the coating may be present on at least one of thefirst or second major surfaces of the substrate in a total amountranging from about 50 g/m² to about 400 g/m²—including all values andsub-ranges there-between. In a preferred embodiment, the dry-statecoating may be present on at least one of the first or second majorsurfaces of the substrate in a total amount ranging from about 75 g/m²to about 200 g/m²—including all values and sub-ranges there-between. Thetotal amount of the coating in the dry-state may be the result of asingle or multiple applications of the wet-state coating—as discussedfurther herein.

The reducing composition of the present invention includes a blend of afirst component and a second component. The first component may includea urea compound having the general formula I:

Wherein R₁ and/or R₂ are selected from the group consisting of H, OH,NH₂, NHR₃ (where R₃ is selected from the group consisting of alkyl(C₁-C₆), alkyloxy, and alkyamine) and COOH; and R₁ and R₅ are selectedfrom the group consisting of H, alkyl (C₁-C₆), and alkyloxy; wherein atleast one of R₄ or R₅ is a hydrogen. In a preferred embodiment, R1, R2,R4, and R5 are each H—i.e., the urea compound is ethylene urea (asreferred to as N,N-Ethylene urea or 2-imidazolidone). The firstcomponent may be present in an amount ranging from about 2 wt. % toabout 18 wt. % (including all values and sub-ranges there-between)—basedon the total weight of the coating in the dry-state. In a preferredembodiment, the first component may be present in an amount ranging fromabout 5 wt. % to about 13 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the coating in thedry-state.

The second component of the reducing composition may comprise particlesof silicon dioxide (also referred to as silica). The silicon dioxide mayhave a particle size ranging from about 0.5 μm to about 120 μm—includingall values and sub-ranges there-between. In a preferred embodiment, thesilicon dioxide may have a particle size ranging from about 30 μm toabout 60 μm—including all values and sub-ranges there-between. Thesilicon dioxide may be in the form of silica gel.

The term “silica gel” according to the present invention refers tosilicon dioxide formed from sodium silicate having pores that arenano-scaled or micro-scaled. The silica gel may serve as adesiccant—i.e., a hygroscopic substance (absorbs water) that induces orsustains a state of dryness in the vicinity surrounding the desiccant.The second component of the reducing composition may be present in anamount ranging from about 5 wt. % to about 40 wt. % (including allvalues and sub-ranges there-between)—based on the total weight of thecoating in the dry-state. In some embodiments, the second component ofthe reducing composition may be present in an amount ranging from about12 wt. % to about 28 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the coating in thedry-state. In a preferred embodiment, the second component of thereducing composition may be present in an amount ranging from about 12wt. % to about 24 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the coating in thedry-state.

The first component and the second component of the reducing compositionmay present in a weight ratio that ranges from about 1:1 to about1:8—including all ratios and ranges there-between. In a preferredembodiment, the first component and the second component may present inthe reducing composition in a weight ratio that ranges from about 1:2 toabout 1:4—including all ratios and ranges there-between.

It has been discovered that by using the combination of the firstcomponent and the second in the reducing composition, the resultingcoating will neutralize a greater variety of VOCs as well as complexodors when compared to building panels comprising using previously knownVOC and/or odor-reducing coating compositions based on zeolites, zincsalts, and mineral oils, cyclodextrin (e.g., Febreeze), andamino-silanes. Specifically, the coating of the present invention hasbeen observed to be effective in reducing and/or neutralizing a widerange of VOCs—including but not limited to ammonia (NH₃), NO_(X),xylene, acetone, butyric acid, benzene, toluene, pyridine, acetic acid,triethylamine, and low molecular weight aldehydes and ketones, such asacetaldehyde, and formaldehyde—as well as a wide range of complex odors,such as bathroom odors (e.g., urine, feces, flatulence), cooking odors(e.g., popcorn, cumin, burnt foods), pet odors (e.g., dog and cat odor,cat food), cleaning materials, and tobacco smoke.

Previous VOC and/or odor-reducing coating compositions were incapable ofneutralizing such a diverse body of odors. For example, amino-silanebased VOC and/or odor-reducing coating compositions may be capable ofneutralizing only aldehyde-based VOC odors. Other examples includezeolite-based VOC and/or odor-reducing coating compositions, which arecapable of neutralizing VOC based odors but not complex odors such asodors from bathroom use or tobacco smoke.

In addition to neutralizing a greater variety of odors, it has beensurprisingly discovered that the coating of the present invention willneutralize those VOCs and/or odors to a greater extent and do so in lesstime and have longer sustainability as compared to previously known VOCand/or odor-reducing compositions—as described in greater detail herein.For example, coatings based on mineral oils are not effective as a VOCand/or odor-reducing coating because mineral oils evaporate quickly andtherefore have no sustainability over the life-span of a permanentlyinstalled building panel. Additionally, coatings based on cyclodextrinare not effective as VOC and/or odor-reducing coatings because, after aninitial VOC and/or odor absorption, the cyclodextrin cannot re-absorbadditional amounts of VOC and/or odors. Therefore, cyclodextrin provideslittle-to-no sustainability over the life-span of a permanentlyinstalled building panel.

The coating of the present invention is also less susceptible moistureconcerns as compared to previously known VOC and/or odor-reducingcoatings. Specifically, the VOC and odor neutralization and/or reductionof the reducing composition is substantially the same at high relativehumidity (RH) as compared to that at low RH. Therefore, coatingcomposition of the present invention may be useful in neutralizing VOCsand odors in a greater variety of climates as compared to the previousVOC and/or odor-reducing coatings where the neutralization and/orreduction was susceptible degradation based on the moisture content ofthe surrounding environment. For example, zeolite based VOC and/orodor-reducing coatings are ineffective at neutralizing VOCs and/or odorsin high RH and, therefore, are unsuitable for high humidity climates(e.g., swamp land, tropical regions, etc.).

As previously discussed, the building panel of the present invention maybe manufactured by applying the wet-state coating composition to thesubstrate. In the wet-state, the coating composition comprises thereducing composition and a carrier comprising water—as well as othercomponents as described further herein. The carrier may be present in anamount ranging from about 25 wt. % to about 75 wt. % based on the totalweight of the wet-state coating composition—thereby yielding a solidscontent of about 25 wt. % to about 75 wt. %—including all percentagesand sub-ranges there-between. In a preferred embodiment, the carrier maybe present in an amount ranging from about 35 wt. % to about 60 wt. %(including all values and sub-ranges there-between)—based on the totalweight of the wet-state coating.

After application of the wet-state coating, the substrate may be driedfor a period of time such that the carrier is driven off (referred to asthe “drying stage”), thereby forming the dry-state coating on thesubstrate. In some embodiments, the wet-state coating may be dried at adrying temperature that is about room temperature. In other embodiments,the wet-state coating may be dried at a drying temperature that is anelevated temperature ranging from about 40° C. to about 180°C.—including all temperature and sub-ranges there-between. The resultingdry-state coating may form a continuous coating or a discontinuouscoating on the substrate.

When performing the drying stage at the elevated temperature, thereduced solids content of the wet-state coating of the present inventionprovides for additional amounts of carrier that help prevent thebuilding panel and reducing composition from over-heating. Statedotherwise, the additional amounts of carrier in the wet-state coatinghelp protect both the substrate and the reducing composition fromoxidizing during the elevated temperatures of the drying stage—whichwould degrade the VOC and odor neutralization/reduction performance ofthe reducing composition. Thus, by using a carrier concentration of atleast about 25 wt. % and up to about 75 wt. % (based on the total weightof the wet-state coating), the building panel of the present inventioncan be manufactured efficiently (i.e. at higher drying temperatures)without increased risk of degrading the VOC andodor-neutralizing/reducing characteristics of the coating.

As the concentration of carrier increases and the solids contentdecreases, the wet-state coating may thin beyond a suitable applicationviscosity. Suitable application viscosity of the wet-state coating mayrange from about 200 cps to about 4,000 cps at roomtemperature—preferably about 400 to about 3,000 cps at roomtemperature—including all values and sub-ranges there-between. Therecited viscosity is measured on a Brookfield viscometer at 10 RPMs. Tomaintain the desired application viscosity in the wet-state, coating mayfurther comprise a rheology modifier. Even at comparatively low solidcontent, the rheology modifier will interact with the carrier andthicken the wet-state coating to achieve the viscosity needed forapplication the wet-state coating onto the substrate.

The rheology modifier may be selected from compounds that do notinterfere with the odor neutralizing performance of the reducingcomposition. Suitable rheology modifiers may include one or more clayparticles (e.g., kaolin), non-ionic surfactant, ionic-surfactant andcombinations thereof. The amount of rheology modifier may depend on thesolids content of the wet-state coating as well as the specific type ofrheology modifier.

According to some embodiments, the rheology modifier may includesilicate minerals, alkali-swellable compounds, and combinations thereofthat are present in an amount ranging from about 0.1 wt. % to about 55wt. % based on the total weight of the coating in thedry-state—including all values and sub-ranges there-between. Accordingto some embodiments, the rheology modifier may be an alkali-swellablecompound that is present in an amount ranging from about 0.1 wt. % toabout 2.0 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the dry-state coating. Inother embodiments, the rheology modifier may be a silicate mineral thatis present in an amount ranging from about 1 wt. % to about 55 wt. %(including all values and sub-ranges there-between)—based on the totalweight of the dry-state coating. In a preferred embodiment, the rheologymodifier may comprise a silicate mineral in an amount ranging from about0.5 wt. % to about 55 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the dry-state coating.

A non-limiting example of silicate mineral includes kaolin particles.The kaolin particles may have an average particle size ranging fromabout 0.5 μm to about 30 μm—including all sizes and sub-rangesthere-between. The kaolin particles may have a density ranging fromabout 2 g/cm³ to about 4 g/cm³—including all densities and sub-rangesthere-between. In a preferred embodiment, the kaolin particles may havea size distribution that has about 0.3% of the particles retained on a325 mesh screen and a density of about 2.6 g/cm³—commercially availableas EG-44 from Thiele Kaolin Company.

In the wet-state, the rheology modifier comprising at least one ofsilicate mineral, alkali-swellable compound, or combinations thereof,may be present relative to the carrier in a weight ratio ranging fromabout 1:1.5 to about 1:10—including all ratios and sub-rangesthere-between.

Other suitable rheology modifiers may comprise surfactant (includingemulsifier). The surfactant may be ionic, non-ionic, or combinationsthereof. The surfactant may be present in an amount ranging from about0.1 wt. % to about 17.0 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the coating in thedry-state.

The non-ionic surfactant may be present in an amount ranging from about0.1 wt. % to about 0.5 wt. % based on the total weight of the dry-statecoating. Suitable non-ionic surfactant may include linear or branchedethoxylated alcohol—such as ethoxylated trimethylol nonanol—commerciallyavailable as Tergitol TMN6. The ionic surfactant may be present in anamount ranging from about 1 wt. % to about 7 wt. % based on the totalweight of the dry-state coating. The ionic surfactant may includesodium-based salts of alkyl (C12 to C16) carboxylates or sulfonates. Theemulsifier may be present in an amount ranging from about 2 wt. % toabout 12 wt. % based on the total weight of the dry-state coating.Non-limiting examples of emulsifier include C14 to C20 fatty acids—suchas 9-octadecenoic acid.

The coating may further comprise other components such as a binder. Thebinder may be present in the coating in an amount ranging from about 4wt. % to about 16 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the coating in thedry-state. The binder may include copolymer formed from a latex (i.e.,aqueous dispersion of polymer), wherein the copolymer is formed frommonomers including vinyl chloride, ethylene, and amide-monomer (e.g.,acrylamide, methacrylamide)—commercially available as VINNOL 4530. Othernon-limiting examples of binder include polymers based on styrene,butadiene, acrylate, methacrylate, acrylic or polyol chemistries, epoxy,urethane, and polyurea.

The coating of the present invention may further comprise filler. Thefiller may comprise one or more inorganic particles. Non-limitingexamples of such inorganic particles include limestone, calciumcarbonate, dolomite, titanium dioxide, talc, perlite, gypsum, calcite,aluminum trihydrate, zinc oxide, and combinations thereof. The inorganicparticles may have a particle size ranging from about 0.1 μm to about300 μm—including all values and sub-ranges there-between. The inorganicparticles may be present in an amount ranging from about 0 wt. % toabout 60 wt. % (including all values and sub-ranges there-between)—basedon the total weight of the coating in the dry-state.

According to some embodiments, the auxiliary inorganic particles may becalcium carbonate. The calcium carbonate particles may be entirely solidor may be porous. The calcium carbonate particles may have an averageparticle size ranging from about 0.5 μm to about 300 μm—including allvalues and sub-ranges there-between. The calcium carbonate particles mayhave a density ranging from about 1 g/cm³ to about 4 g/cm³—including allvalues and sub-ranges there-between. In a preferred embodiment, thecalcium carbonate may be solid and have an average particle size ofabout 6 μm and a density of about 2.7 g/cm³. In some embodiments, theporous calcium carbonate particles may an average particle size about 2μm to about 16 μm—with a d₅₀ (particle size distribution value) of about6.5 μm. The porous calcium carbonate particles may have a surface arearanging from about 120 m²/g to about 160 m²/g—preferably about 144 m²/g.

The coating may further comprise auxiliary components such as defoamerin an amount ranging from about 0.05 wt. % to about 0.2 wt. % (includingall values and sub-ranges there-between)—based on the total weight ofthe coating in the dry-state.

Non-limiting examples of defoamer may include polyalphaolefin formedfrom one or more monomers of 1-hexene, 1-heptene, 1-octene, 1-nonene,1-decene, 1-undecene, 1-tridecene, 1-tetradecene, 1-pentadecene,1-hexadecene, 1-octadecene, 1-heptadecene, and 1-nonadecene; a highdensity polymer selected from oxidized ethylene homopolymers,polyethylene homopolymers, and polypropylene homopolymers; a siliconeoil, polypropylene glycol, and diethylenetriamine; and a non-ionicsurfactant compound selected from polyether modified polysiloxane,polyethylene glycol oleate, and polyoxypropylene-polyoxyethylenecopolymer—as well as mixtures thereof. In a preferred embodiment, thedefoamer may comprise an organo-silicone compound represented by thefollowing formula II

Wherein each R¹ is a monovalent hydrocarbon group of one to eighteen(18) carbon atoms, R² is a monovalent hydrocarbon group of one toeighteen (18) carbon atoms or an organic substituent, and x and y areeach not less than 1, providing x+y equals a number between 3 to 8. Anon-limiting of an organo-silicone defoamer includes octamethylcyclotetrasiloxane—commercially available as Foam Blast 4288.

The coating may further comprise auxiliary components such as a biocidein an amount ranging from about 0.005 wt. % to about 0.05 wt. %(including all values and sub-ranges there-between)—based on the totalweight of the coating in the dry-state. The term biocide refers to acompound that helps prevent undesirable biological growth, for example,algal, barnacle or fungal growth on submerged, partially submerged ordamp exposed structures in aquatic environments or fungal growth inhydrocarbon fuels.

Non-limiting examples of biocides include2,5-dimethyl-1,3,5-thiadiazinane-2-thione (also referred to as“Dazomet”), tetrakis hydroxylmethyl phosphonium sulfate (THPS),1,5-pentanedial (glutaraldehyde), dibromocyanoacetamide (DBNPA),methylene bis(thiocyanate) (MBT), dimethyl-benzyl ammonium chloride(ADBAC quats), cocodiamines, 2-bromo-2-nitro-propane-1,3-diol (BNPD),5-chloro-2-methyl-4-isothiazolin-3-one & 2-methyl-4-isothiazolin-3-one(CIT/MIT), 1,2-benziosothiazolin-3-one (BIT), sodium ortho-phenylphenate(OPP), sodium dimethyldithiocarbamate (SDM), disodium ethylenebisdithiocarbamate, methyl dithiocarbamate (METAM),2-octyl-2H-isothiazol-3-one (OIT), and combinations thereof. In apreferred embodiment, the biocide comprises2,5-dimethyl-1,3,5-thiadiazinane-2-thione.

As previously discussed, the wet-state coating may be applied to atleast one of the first or second major surfaces of the substrate. Thewet-state coating composition may be prepared by mixing together thereducing composition, binder, carrier and rheology modifier as well asother auxiliary components such as binder and optionally filler,biocides, and defoamer. The carrier may be present in an amount rangingfrom about 25 wt. % to about 75 wt. % based on the total weight of thewet-state coating—yielding a solids content of about 25 wt. % to about75 wt. %—including all percentages and sub-ranges there-between. In apreferred embodiment, the carrier may be present in an amount rangingfrom about 35 wt. % to about 65 wt. %, thereby yielding a solids contentof about 35 wt. % to about 65 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the wet-state coating.

The amount of each non-carrier component in the wet-state can becalculated by multiplying the solids % of the wet-state with the amountof the non-carrier component in the dry-state. For example, for a drystate coating composition comprising 8 wt. % of ethylene urea formedfrom a wet-state coating composition having a solids content of 45%—thewet-state coating composition would have comprised 3.6 wt. % of ethyleneurea (45%×8%=3.6%).

The resulting wet-state coating composition may be stirred at roomtemperature for a predetermined period of time to ensure the solidcomponents have a substantially uniform distributed throughout thewet-state coating composition. The wet-state coating composition mayhave a viscosity ranging from about 200 cps to about 4,000 cps at roomtemperature—preferably about 400 to about 3,000 cps at roomtemperature—including all values and sub-ranges there-between. Therecited viscosity is measured on a Brookfield viscometer at 10 RPMs.

The resulting wet-state composition may be applied to at least one majorsurface of the substrate by spray coating, roll coating, dip coating, orbrush coating. The substrate may have a prime coat pre-applied to themajor surface before application of the wet-state coating. The resultingwet-state coating may as a single coat or a plurality of coats (e.g., 2,3, 4, 5, 6, 7, 8, etc.) so long as the resulting amount of wet-statecoating present on the substrate ranges from about 100 g/m² to about1000 g/m²—including all values and sub-ranges there-between. In apreferred embodiment, the total amount of wet-state coating present onthe substrate ranges from about 200 g/m² to about 600 g/m²—including allvalues and sub-ranges there-between.

The wet-state coating of the preset invention exhibits improved waterretention and does not dewater quickly. Therefore, wet-state coating ofthe present invention is particularly suitable for application to thesubstrate by roll-coating because wet-state coating will not dewaterduring processing and accumulate on the roll. Rather, enhanced waterretention allows for the wet-state coating to be readily transferablefrom the roller to the substrate on each roll-application.

After each application of the wet-state coating to the substrate, thewet-state coating and the substrate may be dried for a predeterminedperiod of time. According to some embodiments, the wet-state coating maybe dried at room temperature. According to other embodiments, thewet-state coating may be dried with the addition of heat at the dryingtemperature ranging from about 40° C. to about 180° C.—including allvalues and sub-ranges there-between. Drying may be facilitated by theaddition of external heat from one or more heating lamps or an oven.

Alternatively, one or more additional applications of wet-state coatingmay be applied prior to drying the previously applied wet-state coating.After drying, the dry-state coating may be present on the substrate inan amount ranging from about 50 g/m² to about 400 g/m²—including allvalues and sub-ranges there-between.

In an alternative embodiment, the present invention may be directed to aVOC and odor-reducing coating comprising an odor-reducing composition(referred to herein as “reducing composition”) that consists essentiallyof silica gel. In such embodiments, the aforementioned discussion withrespect to all other components in the coating (e.g., rheology modifier,binder, biocides, filler, carrier, defoamer, etc.) as well as method ofproduction—in both in the wet-state and the dry-state—apply to thealternative embodiment that has a reducing composition consistingessentially of silica gel. According to the present invention, thephrase “consisting essentially of” means compounds that do not interferewith the odor neutralizing performance of the reducing composition.

According to such alternative embodiments, the silica gel may be presentin an amount ranging from about 5 wt. % to about 40 wt. % (including allvalues and sub-ranges there-between)—based based on the total weight ofthe coating in the dry-state. The silica gel may be present in an amountranging from about 12 wt. % to about 28 wt. % (including all values andsub-ranges there-between)—based on the total weight of the coating inthe dry-state. In a preferred embodiment, the second component of thereducing composition may be present in an amount ranging from about 12wt. % to about 24 wt. % (including all values and sub-rangesthere-between)—based on the total weight of the coating in thedry-state.

The building panel of the present invention may be a ceiling panel ortile, wall panel, wall covering (e.g., wallpaper) or directly to a wall(e.g., painted dry wall, wood wall paneling, such as wainscot, baseboardmolding, crown molding). In other embodiments, the coating compositionmay be applied directly to a glass surface (e.g., a door, a window,etc.). In other embodiments of the present invention, the coatingcomposition may be applied various textiles—such as felts, upholstery,or window hangings (e.g., curtains), and various paper products (e.g.,paper towels, coated paper, cardboard, and the like), decorativeshower-curtaining liners. In other embodiments, the coating compositionmay be applied to a window blind (formed from cellulosic material,polymeric material, or inorganic material). The coating composition maybe applied to other various indoor surfaces for the purpose of reducingVOCs and odor in a closed-environment. In other embodiments, the coatingcomposition may be applied to packaging products (e.g., styrofoam,recycled packaging).

As used throughout, ranges are used as shorthand for describing each andevery value that is within the range. Any value within the range can beselected as the terminus of the range. In addition, all references citedherein are hereby incorporated by referenced in their entireties. In theevent of a conflict in a definition in the present disclosure and thatof a cited reference, the present disclosure controls.

While the invention has been described with respect to specific examplesincluding presently preferred modes of carrying out the invention, thoseskilled in the art will appreciate that there are numerous variationsand permutations of the above described systems and techniques. It is tobe understood that other embodiments may be utilized and structural andfunctional modifications may be made without departing from the scope ofthe present invention. Thus, the spirit and scope of the inventionshould be construed broadly as set forth in the appended claims.

EXAMPLES Examples 1-8

Examples 1-6 demonstrate the synergistic benefit of the reducingcomposition comprising ethylene urea and silica of the present inventionover previously known VOC and/or odor-reducing compositions. Examples7-8 demonstrate the surprising performance of the reducing compositionconsisting essentially of silica gel for reducing ammonia-based VOCand/or odors.

Described in Tables 1 and 2 (below) are eight (8) exemplary VOC andodor-reducing coatings of the present invention (Ex. 1-Ex. 8), alongwith the compositions for fourteen (14) comparative compositions (Comp.Ex. 1-Comp. Ex. 14), as well as two controls (Control 1 and Control 2)where no VOC and/or odor-reducing coating composition applied. Thecompositions of Examples 1-8 and Comparative Examples 1-14 include thefollowing components:

-   -   i. Silica gel    -   ii. Ethylene Urea    -   iii. Zeolite    -   iv. Zinc Salt—an odor neutralizing composition commercially        available as Flexisorb OD-300    -   v. Kaolin—rheology modifier comprising kaolin particles having a        particle size distribution where 0.3% is retained on a 325 mesh        screen.    -   vi. Solid CaCO₃—solid calcium carbonate having a particle size        of about 6 μm and a density of about 2.7 g/cm³    -   vii. Porous CaCO₃—porous calcium carbonate having a particle        size have a particle size distribution that includes a d₅₀ of        about 6.6 μm and a d₉₈ of about 15 μm and a surface area of        about 144 m²/g.—commercially available as OMYA TP-2553/J.    -   viii. Binder—terpolymer of vinyl chloride, ethylene, and        amide-monomer (e.g., acrylamide, methacrylamide)—commercially        available as VINNOL 4530    -   ix. Surfactant 1—ethoxylated trimethylol nonanol—commercially        available as Tergitol TMN6)    -   x. Surfactant 2—surfactant (such as 9-octadecenoic acid    -   xi. Surfactant 3—alkyl (C14-C16) olefin sulfonate,    -   xii. Auxiliary—various amounts of defoamer (such as octamethyl        cyclotetrasiloxane—commercially available as Foam Blast 4288)        and biocide (such as 2,5-dimethyl-1,3,5-thiadiazinane-2-thione).

Specifically, the coating composition of each example was prepared in awet-state and applied to a major surface of a substrate. The wet-stateodor-reducing coating was then dried and the carrier driven off, therebyyielding a dry-state coating. Each substrate coated with dry-statecoating was placed in a glass desiccator with a predetermined amount ofVOC. A fan was provided in the glass desiccator for circulation. Usingcolorimetric gas detector tubes, the amount of VOC was measured afterpredetermined time intervals. A control was also prepared with nodry-state VOC and/or odor-reducing coating composition, to determine theun-aided reduction in VOC over time. The absorption information is shownbelow in Tables 1 and 2.

TABLE 1 Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. AldehydeReduction Ex. 1 Ex. 2 Ex. 3 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7Ex. 8 Control 1 Dry-State Ethylene Urea  8%   8%   8%  12% — —   8%   8%  8%   6%  6% — Silica Gel 19.4%  21.1% 21.1% — 21.1% 21.1% — — — — — —Zeolite — — — — — — — — — — 50.1%  — Zinc Salt — — — — — — — — —  6.4% 6.4% Kaolin 49.2%  25.5% 27.3% 74.2% 53.5%  30% 46.8% 49.7% — 31.1%31.1%  — Solid CaCO₃ —  20% — — — 23.5% 36.7% 33.8% — — — — Porous CaCO₃— — 18.2% — — — — — 83.5% 50.1% — — Binder 8.3%   9%   9% 12.6%   9%  9%   8%   8%   8%   6%  6% Surfactant 1 0.4%  0.4%  0.4%  0.5%  0.4% 0.4%  0.4%  0.4%  0.4%  0.3%  0.3% — Surfactant 2 9.7% 10.6% 10.6% —10.6% 10.6% — — — — — — Surfactant 3 4.8%  5.3%  5.3% —  5.3%  5.3% — —— — — — Auxiliary 0.2%  0.1%  0.1%  0.7%  0.1%  0.1%  0.1%  0.1%  0.1% 0.1%  0.1% — Total Solids 100%   100%  100%  100%  100%  100%  100% 100%  100%  100% 100% — Wet-State* Solids % 51.6%  44.4% 41.3% 51.5%51.3% 51.3% 50.6% 55.9% 28.6% 45.5% 53.4%  — Water % 48.4%  55.6% 58.7%48.5% 48.7% 48.7% 49.4% 44.1% 71.4% 54.5% 46.6%  — Aldehyde Reduction  1Hour  75%  75% 87.5% 37.5%   0%   0%   0% 67.5%  50% 42.5%  25% 0%  4Hours  85%  85%  100% 47.5%  25%   0% 37.5%  75% 67.5% 62.5%  50% 0%  6Hours 100%   90%  100%  55%  25% 12.5% 37.5%  85%  75%  100% 100% 0%  8Hours 100%  96.3%  100%  70%  25% 12.5%  70%  100%  100%  100% 100%12.5%   24 Hours 100%   100%  100%  85%  30% 83.3% 62.5%  100%  100% 100% 100% 83.3%   *The specific amount of each component in thewet-state can be calculated by multiplying the solids % with the amountweight percentage in the dry-state. For instance, the ethylene urea inEx. 1 is present in the wet-state by an amount of 4.13 wt. % based onthe total weight of the wet-state coating composition (8% × 51.6% =4.13%)

TABLE 2 Comp. Comp. Comp. Comp. Comp. Comp. Ammonia Reduction Ex. 4 Ex.5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Ex. 14 Control 2Dry-State Ethylene Urea   8%   8%   8% — —  12%   8%   8%   8%   6%   6%— Silica Gel 19.4% 21.1% 21.1% 21.1% 21.1% — — — — — — — Zeolite — — — —— — — — — — 50.1% — Zinc Salt — — — — — — — — —  6.4%  6.4% Kaolin 49.2%25.5% 27.3% 53.5%  30% 74.2% 46.8% 49.7% — 31.1% 31.1% — Solid CaCO₃ — 20% — — 23.5% — 36.7% 33.8% — — — — Porous CaCO₃ — — 18.2% — — — — —83.5% 50.1% — — Binder  8.3%   9%   9%   9%   9% 12.6%   8%   8%   8%  6%   6% Surfactant 1  0.4%  0.4%  0.4%  0.4%  0.4%  0.5%  0.4%  0.4% 0.4%  0.3%  0.3% — Surfactant 2  9.7% 10.6% 10.6% 10.6% 10.6% — — — — —— — Surfactant 3  4.8%  5.3%  5.3%  5.3%  5.3% — — — — — — — Auxiliary 0.2%  0.1%  0.1%  0.1%  0.1%  0.7%  0.1%  0.1%  0.1%  0.1%  0.1% —Total Solids  100%  100%  100%  100%  100%  100%  100%  100%  100%  100% 100% — Wet-State* Solids % 51.6% 44.4% 41.3% 51.3% 51.3% 51.5% 50.6%55.9% 28.6% 45.5% 53.4% — Water % 48.4% 55.6% 58.7% 48.7% 48.7% 48.5%49.4% 44.1% 71.4% 54.5% 46.6% — Ammonia Reduction  1 Hour 90.6% 87.5%76.3% 93.7% 72.5% 84.4% 72.5%  50%  75% 62.5% 72.5% 72.5%  4 Hours 93.1%90.3% 81.3% 95.3% 86.3% 85.9% 72.5%  65%  75%  75%  75% 87.5%  6 Hours 95% 90.5% 87.5% 96.3% 88.8% 88.8%  75% 78.8% 87.5% 81.3% 81.3% 87.5%  8Hours 97.5% 91.3% 93.8% 96.3%  90%  89%  75% 87.5% 93.8% 87.5% 87.5%87.5% 24 Hours  100% 95.8% 97.5%  98% 91.7% 94.5 81.3% 93.8% 97.5%  95% 95% 91.7% *The specific amount of each component in the wet-state canbe calculated by multiplying the solids % with the amount weightpercentage in the dry-state. For instance, the ethylene urea in Ex. 1 ispresent in the wet-state by an amount of 4.13 wt. % based on the totalweight of the wet-state coating composition (8% × 51.6% = 4.13%)

As demonstrated by Tables 1 and 2, the reducing composition of thepresent invention is capable of neutralizing a variety of VOCs (e.g.,ammonia and aldehyde). Furthermore, as demonstrated by Table 1, thereducing composition of the present invention provides superior VOCreduction (reaching 100% in some examples) as compared to zinc-salts,zeolites, and individual systems based solely on ethylene urea.

Furthermore, as demonstrate by Table 1, the reducing composition of theethylene urea (i.e., first component of the reducing composition) andthe silica gel (i.e., the second component of the reducing composition)creates an unexpected synergistic effect in that in the amount of VOCthat can be neutralized in a given amount of time. Specifically, theamount of VOC neutralized by the reducing composition of the first andsecond components (see Examples 1, Hour 1 to Hour 4) is greater than thesum of the VOC that was neutralized by each of the first component andthe second components used separately (see Ex. 1 and Comp. Ex. 1 and2—summarized below in Table 3).

TABLE 3 Aldehyde Reduction 1 Hour 4 Hours 6 Hours Comp. Ex. 1 37.5%47.5% 55% Comp. Ex. 2   0%  25% 25% Sum of Comp. Ex. 1 & 2 37.5% 72.5%80% Example 1  75%  85% 100% 

Thus, as demonstrated by Table 3, the reducing composition of thepresent invention surprisingly creates an synergistic advance in VOC andodor neutralization—as evidenced by the greater amount of VOC reductioncompared to the summation of VOC-neutralizing power for an individualethylene urea based reduction composition (i.e., Comp. Ex. 1) and anindividual silica gel based reduction composition (i.e., Comp. Ex. 2).

Additionally, as demonstrate by Table 1, the at least partialsubstitution of kaolin and/or solid CaCO3 particles for porous CaCO3particles results in faster VOC neutralization/reduction by the coating.The improvement in VOC neutralization is summarized below in Table 4.

TABLE 4 Ex. 2 Ex. 3 Ex. 1 (Kaolin/ (Kaolin/ Aldehyde Reduction (Kaolin)Solid CaCO₃) Porous CaCO₃) 1 Hour  75% 75% 87.5%  4 Hour  85% 85% 100% 6Hours 100% 90% 100% 8 Hours 100% 96.3%  100%

Thus, as demonstrated by Table 4, the addition of porous CaCO₃surprisingly creates an synergistic advance in VOC and odorneutralization—as evidenced by the greater amount of VOC reduction inExample 3 compared to the amount of VOC reduction in either Example 1 orExample 2.

Additionally, as demonstrate by Table 2, the reducing compositionconsisting essentially of silica gel provides an unexpected performancein VOC reduction in the amount of ammonia that can be neutralized in agiven amount of time. Specifically, the amount of ammonia neutralized bythe reducing composition consisting essentially of silica gel (seeExamples 7 and 8, Hour 1 to Hour 4) is greater than using ethylene ureaalone (Comparative Example 9) and substantially equal to the superiorVOC and odor reducing performance of the Examples 4-6

Example 9

Example 9 demonstrates the effect of relative humidity (RH) onzeolite-based VOC and/or odor-reducing agents on aldehyde odors. Asecond building panel comprising the second zeolite-based reducing agentwas tested.

The first building panel was placed in a controlled environment having0% RH and exposed to a first predetermined amount of formaldehyde (1.15ppm). After a predetermined time period, the remaining amount offormaldehyde in the controlled environment was measured and compared tothe initial predetermined amount, allowing for the calculation of thepercentage of formaldehyde reduced in the controlled environment. Thecontrolled environment was then cleared of the remaining formaldehyde.These steps were then repeated reusing the same first building panelwith a fresh predetermined amount of formaldehyde (1.15 ppm) beingreintroduced into the controlled environment at 0% RH. The sameevaluation was performed on a fresh first building panel at 50% RH usinga predetermined amount of formaldehyde (1.2 ppm). The percentage offormaldehyde removed from the room environment for each predeterminedtime period for the 0% RH and the 50% RH tests are provided in Table 5below.

TABLE 5 Time Period 24 48 72 96 168 192 216 hours hours hours hourshours hours hours Formaldehyde 84.3% 82.6% 81.7% 80.9% 78.3% 78.3% 77.4%Reduction @ 0% RH Formaldehyde  45%  33% 27.5% 22.5% 11.7%  9.2% —Reduction @ 50% RH

Based on the extrapolation of the recorded formaldehyde reductionpercentages, the first building panel comprising the first zeolite-basedreducing agent would reach saturation (i.e., no longer to absorbformaldehyde) in about 43 days (1030 hours) at 0% RH. At 50% RH thefirst building panel comprising the first zeolite-based reducing agentwould reach saturation at about 12 days (290 hours). Thus, asdemonstrated by Table 5, the atmospheric humidity in a normal roomenvironment negatively impacts the zeolite's ability to reducing VOCand/or odor. Therefore, zeolites are ineffective as VOC and/or odorreducing agents for building panels that are installed in roomenvironments having standard-to-high humidity, such as swamp land ortropical areas.

The second building panel was placed in a controlled environment having0% RH and exposed to a first predetermined amount of formaldehyde (1.1ppm). After a predetermined time period, the remaining amount offormaldehyde in the controlled environment was measured and compared tothe initial predetermined amount, allowing for the calculation of thepercentage of formaldehyde reduced in the controlled environment. Thecontrolled environment was then cleared of the remaining formaldehyde.These steps were then repeated reusing the same second building panelwith a fresh predetermined amount of formaldehyde (1.1 ppm) beingreintroduced into the controlled environment at 0% RH. The sameevaluation was performed on as fresh second building panel at 50% RHusing a predetermined amount of formaldehyde (1.2 ppm). The percentageof formaldehyde removed from the room environment for each predeterminedtime period for the 0% RH and the 50% RH tests are provided in Table 6below.

TABLE 6 24 48 72 96 120 144 168 192 216 264 hours hours hours hourshours hours hours hours hours hours Formaldehyde 90.2% — — 70% 69% —68.2% 67.3% — 65.5% Reduction @ 0% RH Formaldehyde 45.8% 28.3% 27.6% — —6.7%  4.2%  2.5% 1.7% — Reduction @ 50% RH

Based on the extrapolation of the recorded formaldehyde reductionpercentages, the second building panel comprising the secondzeolite-based reducing agent would reach saturation at about 47 days(1125 hours) at 0% RH. At 50% RH, the second building panel comprisingthe second zeolite-based reducing agent would reach saturation at about9 days (210 hours)—thereby confirming that the presence of standardatmospheric humidity will negatively impacts the zeolites ability to actas a VOC and/or odor-reducing agent in building panels.

Example 10

Example 10 tests the effect of humidity on the silica gel based VOC andodor-reducing agent (representative of the present invention) onaldehyde. Glass slides coated with silica gel based reducing agent wereplaced in separate controlled environments—the first having 35% RH at82° F. and the second having 90% RH at 82° F. A predetermined amount offormaldehyde (0.046 grams) was placed in each controlled environment andthe level of formaldehyde was measured at predetermined time intervals.The amount of formaldehyde (in ppm) removed from the controlledenvironment for the 35% RH and the 90% RH tests are provided in Table 7below.

TABLE 7 Time Period 10 20 30 60 120 min min min min min Formaldehyde 1.52.0 3.5 4.0 5.5 Absorption @ 35% RH and 82° F. Formaldehyde 1.0 1.5 3.04.5 6.0 Absorption @ 90% RH and 82° F. Control 1.6 1.6 2.0 4.0 8.0

As demonstrated by Table 7, the presence of a relative humidity as highas 90% has no effect on the silica gel acting as reducing agent at highRH. Specifically, at minimum, the silica gel exhibits substantially thesame performance at 90% RH as at 35% RH and, in some cases, out-performsat a higher RH (see, 60 min, 120 min)—which is contrary to thezeolite-based reducing agent that performs substantially worse at higherRH. Therefore, the silica gel based reducing agents of the presentinvention provide very useful for building panels that are to beinstalled in standard room environments that containing normal amountsof atmospheric humidity—and especially useful in high humidity areas,such as swamp land or tropical areas.

Example 11

Example 11 tests the effect of humidity was tested on the silica gelbased reducing agent on the reduction of ammonia. Glass slides coatedwith silica gel based reducing agent were placed in separate controlledenvironments—the first having 20% RH at 82° F., the second having 35% RHat 82° F., and the third having 90% RH at 82° F. A predetermined amountof ammonia (0.046 grams) was placed in each controlled environment andthe level of ammonia was measured at predetermined time intervals. Theamount of ammonia (in ppm) remaining in each controlled environment isprovided in Table 8 below.

TABLE 8 Time Period 0 10 20 30 60 120 20 min min min min min min hoursNH₃ Absorption @ 130 60 41 30 20 12 4 20% RH and 82° F. NH₃ Absorption @130 55 45 40 30 20 5 35% RH and 82° F. NH₃ Absorption @ 130 75 60 58 4035 10 90% RH and 82° F.

As demonstrated by Table 8, even at a relative humidity as high as 90%has no effect on the silica gel based reducing agent to reduce VOC andodor-reducing. Specifically, at minimum, the silica-based reducing agentperforms substantially the same at 20% RH, 35% RH, and 90% RH.Therefore, the silica gel based reducing agents of the present inventionprovide very useful for building panels that are to be installed instandard room environments that containing normal amounts of atmospherichumidity—and especially useful in high humidity areas, such as swampland or tropical areas.

As those skilled in the art will appreciate, numerous changes andmodifications may be made to the embodiments described herein, withoutdeparting from the spirit of the invention. It is intended that all suchvariations fall within the scope of the invention.

What is claimed is:
 1. A VOC and odor-reducing building panelcomprising: a substrate; and a coating applied to the substrate, thecoating comprising a blend of: a first component comprising ethyleneurea; a second component comprising silica; and a rheology modifier. 2.The building panel according to claim 1, wherein the coating is solid atroom temperature and comprises less than about 5 wt. % of a carrierbased on the total weight of the coating, the carrier selected fromwater.
 3. The building panel according to claim 1, wherein the firstcomponent is present in an amount ranging from about 2 wt. % to about 20wt. % based on the total weight of the coating.
 4. The building panelaccording to claim 1, wherein the second component is present in anamount ranging from about 5 wt. % to about 40 wt. % based on the totalweight of the coating.
 5. The building panel according to claim 1,wherein the coating is present on the substrate in an amount rangingfrom about 50 g/m² to about 400 g/m².
 6. The building panel according toclaim 1, wherein the silica is silica gel.
 7. The building panelaccording to claim 1, wherein the rheology modifier selected fromsilicate mineral, alkali-swellable compounds, and combinations thereof.8. The building panel according to claim 7, wherein the rheologymodifier is present in an amount ranging from about 0.1 wt. % to about55 wt. % based on the total weight of the coating.
 9. The building panelaccording to claim 1, wherein the coating exhibits substantially thesame odor-reducing performance in an environment having 90% relativehumidity as an environment having at 0% relative humidity.
 10. Thebuilding panel according to claim 1, wherein the substrate is a porousstructure and the building panel is an acoustical ceiling panel.
 11. AVOC and odor-reducing building panel comprising: a substrate; and acoating applied to the substrate, the coating comprising anodor-reducing composition comprising a blend of ethylene urea and silicain a weight ratio ranging from about 1:1 to about 1:8; wherein thecoating is substantially solid at room temperature and comprises lessthan 5 wt. % of moisture based on the total weight of the coating. 12.The building panel according to claim 11, wherein the coating furthercomprises inorganic particles selected from kaolin, calcium carbonate,and a combination thereof.
 13. The building panel according to claim 12,wherein the odor-reducing composition and inorganic particles arepresent in a weight ratio ranging from about 1:1 to about 1:3.
 14. A VOCand odor-reducing building panel comprising: a substrate; and a coatingapplied to the substrate, the coating comprising: silica gel; asurfactant; and a rheology modifier.
 15. The building panel according toclaim 14, wherein the coating is solid at room temperature and comprisesless than about 5 wt. % of a carrier based on the total weight of thecoating, the carrier selected from water.
 16. The building panelaccording to claim 14, wherein the silica gel is present in an amountranging from about 5 wt. % to about 40 wt. % based on the total weightof the coating.
 17. The building panel according to claim 14, whereinthe coating is present on the substrate in an amount ranging from about50 g/m² to about 400 g/m².
 18. The building panel according to claim 14,wherein the coating exhibits substantially the same odor-reducingperformance in an environment having 90% relative humidity as anenvironment having at 0% relative humidity.
 19. The building panelaccording to claim 14, wherein the rheology modifier selected fromsilicate mineral, alkali-swellable compounds, and combinations thereof.20. The building panel according to claim 19, wherein the rheologymodifier is present in an amount ranging from about 0.1 wt. % to about55 wt. % based on the total weight of the coating.